@media screen and (min-width: 750px) {
  html {
    font-size: 40PX!important;
  }
}
@media screen and (max-width: 320px) {
  html {
    font-size: 32PX!important;
  }
}

img{
  vertical-align: middle;
}
*{
  box-sizing: border-box;
  color: rgba(0, 0, 0, .7);
}
.center_box{
  max-width: 750PX;
  min-width: 320PX;
  margin: 0 auto;
}
.bottom_shadow{
  box-shadow: 0PX 1PX 0PX 0PX rgba(0, 0, 0, .3);
}
.top_shadow{
  box-shadow: 0PX -1PX 0PX 0PX rgba(0, 0, 0, .3);
}
.bottom_border{
  border-bottom: 1PX solid #ccc
}
.top_border{
  border-top: 1PX solid #ccc
}
.b_margin{
  margin-bottom:5px;
}
.t_margin{
  margin-top: 5px;
}

.clearfix:before,.clearfix:after{content:"";display:table;} .clearfix:after{clear:both;} 
